Modify RE layer to use POST operation for set-request

Modify RE layer to use POST operation for set-request

POST operation is for updation.
It is what the set-request exactly does.

Change-Id: I32615b284b5b7222c4a151bc990b1e4f1014ac41
Signed-off-by: coderhyme <jhyo.kim@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/4347
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>
Tested-by: Uze Choi <uzchoi@samsung.com>
(cherry picked from commit 8cbb210fb8d9cac8ef44649307fe9b258e28db8d)
Reviewed-on: https://gerrit.iotivity.org/gerrit/4397